The present invention relates to a vacuum distillation process. The process is particularly suited for distilling a feed containing hydrocarbons, which feed has a temperature in the range of from 380.degree. to 425.degree. C., at a subatmospheric pressure in the range of from 650 to 5 200 Pa. The feed is sometimes referred to as long residue.
Such a vacuum distillation process comprises introducing a preheated feed which contains liquid and vapor into an inlet section of an upright distillation column operating at a subatmospheric pressure, removing liquid from a bottom section of the distillation column, allowing vapor to pass through at least two condensation sections arranged above each other in the distillation column between the inlet section and a top section, removing vapor from the top section, spraying into each condensation section cooled liquid, and removing liquid from each condensation section, wherein the cooled liquid which is sprayed into each condensation section comprises liquid removed from that condensation section.
The cooled liquid sprayed into each condensation section is sprayed into the vapor passing through the condensation section. As a result part of the vapor is condensed and this part is removed from the distillation column with the liquid removed from the condensation section.
The remaining vapor is removed from the top, uppermost section by vacuum, e.g., vacuum pump and more preferably a steam ejector. It was found that this vapor still contained a considerable amount of valuable hydrocarbon components.
It is an object of the present invention to provide a vacuum distillation process wherein the vapor removed from the top section contains only a small amount of valuable hydrocarbon components.